1quickz

i have a 93 z28 and just changed the opti spark and new plugs the car idles fine but when u drive it and try to give it gas it backfires and wants to die.just changed the coil also. run out of ideas

camar0corey

iTrader: (22)

oh no this sounds like what I have going on.

Not popping any codes??

Black1997T/A

Try unplugging the MAF. This will make the computer default to speed density. If it runs fine with it unplugged it has to be the MAF. Let us know what happens.

1quickz

there is no maf on a 93 only year with out one it is not popping any codes

undercoverz-28

timing would be my guess. a car out of time can sometimes still idle ok but once under a load the miss in the timing becomes noticable. i think theres something to do with the timing behind the opti. when my friend did his he told me about it but his is a 94 or 95. also, does that year have the vaccume line to it. if so might wanna check that.

camar0corey

iTrader: (22)

You can't really screw the timing up, it all is indexed only one way, the ecu controls the timing.

Its not like a older distributer that you can adjust timing just by moving the cap around or anything like that.

Black1997T/A

My fault, didn't read carefully just skimmed through it. Since it's a '93 Im thinking the MAP sensor took a ****.

1quickz

figured it out it was the damn ingnition module replaced it runns great